Vibration damping device



Patented May 19, 1942 VIBRATION DAMPING DEVICE Louis A. McNabb, Chicago, Ill., assignor to The Bell is; Howell Company, Chicago, 111.,

poration of Illinois Application June 18, 1940, Serial No. 341,216

2 Claims.

With this object in view the invention consistsin certain features of novelty in the construction, combination and arrangement of parts by which the said object and certain other objects, hereinafter appearing, are effected all as fully described with reference to the accompanying drawing and more particularly pointed out in the appended claims. 4

In the said drawing- Figure 1 is a partial sectional view of a photographic sound reproducing machine having the exciter lamp thereof equipped with a vibration damping device of my invention and taken substantially on the line Il of Figure 2;

Figure 2 is a partial side elevation of the same with parts shown in section;

Figure 3 is a side elevation of the vibration damping device of my invention; and

Figure 4 is a section of said vibration damping device substantially on the line 4-4 of Figure 3.

Referring to Figures 1 and 2 of the drawing, l designates the frame of a photographic sound reproducing machine. A shaft 2 is rotatably mounted on this frame and a sound drum 3 is mounted on a projecting end thereof for rotation therewith. A photographic sound record bearing film strip 4 is fed at a constant rate about the drum 3 by u'sual feed mechanism not shown.

A usual optical translating device has operative relation with the film strip while engaged on the drum, and consists as follows: An optical slit projecting device 5 projects light in the form of a slit from an exciter lamp 6 through the sound record bearing portion of the film strip which overhangs the drum, as will be seen in Figure l, and a reflector l transmits the resulting sound image projected from the fed film strip to a photo-electric tube 8 from which the sound image is translated into sound by the usual instrumentalities.

The exciter lamp 6 is equipped with the vibration damping device of my invention which consists as follows:

An elongated cylindrical element is formed by two opposed semi-cylindrical members 9 and II, formed of rigid material such as metal. The major portion of these members have the opposing surfaces thereof concave axially, as designated at 12, to provide the cylindrical element with a longitudinally extending bore open at the lower end thereof, and these members are provided at their upper ends with transverse wall portion 1 3 extending across the bore of said cylindrical element. The parting between the members 9 and H forms slits I4 extending longitudinally of the cylindrical element formed thereby extending from the lower or open bore thereof, whereby the cylindrical element is provided with angularly spaced longitudinally extending slits through the cylindrical wall thereof, these slits extending from the lower or open bore end thereof and rendering the cylindrical element expansible.

The members 9 and II are provided with alined exterior semi-cylindrical flanges I5 substantially midway between the upper and lower ends of the same to form a weight portion, and these flanges are provided with alined peripheral grooves IS in which a substantially circular spring I! is engaged to maintain the members 9 and II in assembly to form the cylindrical element and to permit resilient expansion of the same, one end of this spring being turned inwardly, as designated at l8, and engaging in a radial bore 19 of the member II to maintain the spring in position angularly.

Vibration absorbing contacting material, such as cork, is secured on the interior concave surfaces l2 of the members 9 and II, as designated at 2|, and on the interior of the transverse wall portions l3, as designated at 22, whereby the cylindrical element is provided with vibration absorbing contacting material on the interior thereof at the bore and at the transversely extending portion of the same.

The members 9 and l l are provided at one side of the parting and substantially midway between the upper and lower ends thereof with opposing semi-circular openings 23' forming a light opening through the cylindrical wall of the cylindrical element.

The vibration damping device is removably engaged downwardly over the exciter lamp 6 with the vibration absorbing contacting material 2| in pressure contact with the cylindrical side of the lamp and with the vibration absorbing contact material 22 in pressure contact with the top of the lamp, the resiliency of the cylindrical wall of the cylindrical element, exemplified by the members 9 and I l and the slits I4 therebetween as resiliently related by the spring [1, maintaining the pressure contact of the material 2| with the cylindrical side of the lamp. When the damping device is installed, the light opening thereof, exemplified by the openings 23, is alined with the filament 24 of the lamp and with the slit projecting device 5 for the passage of light therebetween, the damping device forming a light shield.

The advantages of the damping device above described are generally obvious from the de scription thereof. However, it is to be noted that the weighting of the cylindrical member by the flange thereof, exemplified by the flanges 15 of the members 9 and H, tends toward damping vibrations usually encountered, particularly where the weighting portion is located as described.

While I have thus described my invention, I do not wish to be limited to the precise details described as changes may be readily made without departing from the spirit of my invention, but having thus described my invention I claim as new and desire to secure by Letters Patent the following:

1. A vibration damping device comprising an elongated element provided with a longitudinally extending bore open at one end and engageable over an electric light beam element containing tube, and provided with a longitudinally extending slit through the wall thereof formed by said bore and with a light opening at said slit and alinable with said light beam element.

2. A vibration clamping device comprising an elongated element of rigid material provided with a longitudinally extending bore open at one end and provided with a portion extending transversely across said bore and spaced from said open bore end and engageable over an electric light beam element containing tube and comprising a plurality of members extending longitudinally of said bore, vibration absorbing contacting material on the interior of said members at said vbore and at said transversely extending portion, said members being provided with alined exterior peripheral flanges substantially midway between said open bore end and said transversely extending portion and forming a weight portion, a circular spring engaged in alined exterior peripheral grooves on said members substantially mid- Way between said open bore end and said transversely extending portion for yieldably maintaining said members circumferentially of said bore, and said members being provided at the parting thereof and substantially midway between said open bore end and said transversely extending portion with opposing openings forming a light opening alinable with said light beam element.

' LOUIS A. MCNABB. 

